Azo dyestuffs



UNITED STATES PATENT OFFICE AZO DYESTUFFS Eduard Moser, Basel, Switzerland, assignor to Ciba Limited, a Swiss firm N Drawing. Application April 8, 1949, Serial No. 86,401. In Switzerland April 16, 1948 6 Claims. (Cl. 260-158) It is known that there are relatively few dyecompound. The alkyl group in the -position of stuffs which yield a pure greenish yellow tint, and the benzene residue is, for example, an alkyl it has therefore been necessary to use dyestufis group containing only a few carbon atoms, such yielding such tints, notwithstanding that their as a butyl, propyl, isopropyl or ethyl group, and dyeing properties are not wholly satisfactory. 5 advantageously a methyl group.

According to the present invention azo-dye- The diazotization of the dehydrothiotoluidine stuffs having especially valuable properties are disulfonic acid may be carried out in known manmade by coupling diazotized dehydrothio-paranor, for example by means of hydrochloric acid toluidine disulfonic acid, which contains a suland sodium nitrite. Coupling with the aforesaid fonic acid group in each benzene nucleus and of 10 acetoacetyl-compounds is advantageously conwhich one sulfonic acid group is in ortho-posiducted in a weakly acid, for example, acetic acid, m t th diazo-group, with the acetoacetylto neutral or weakly alkaline medium. The dyecompound of a 1-amino-2-alkoxy-4-ha1ogen-5- stufi so obtained is worked up in the usual manalkyl-benzene. ner.

The dehydrothio-para-toluidine disulfonic acid The dyestuffs of the invention correspond to used as starting material can be obtained in acthe general formula CH: 8 H0 CH3 Hts C @N=N i M N/ 40E 0 NH halogen alkyl cordance with U. S. Patent No. 1,159,386 either in which the halogen is advantageously fluorine by sulfonating with fuming sulfuric acid the deor bromine, but especially chlorine, and each alhydrothio-para-t0luidine-monosulfonic acid obkyl group advantageously contains only a few tainable by baking the acid sulfate o-f dehydrocarbon atoms, the alkyl group being preferably a thio-para-toluidine, or by baking the acid sulfate methyl group and the O-alky1 group being of the dehydrothio-para-toluidine-monosulfonic preferably a methoxy group. The dyestuffs can acid obtainable by sulfonating dehydrothio-para- 3 be used for printin n e p i l y f r y n a toluidine with fuming sulfuric acid. According very Wi v ri y f fi r h as W001 n to German Patent No. 281,048 both methods lead leather, but espe ial y lul s fi rs u h as to the same disulfonic acid. It corresponds to cotton and artificia1 silk or staple fibers of rethe formula generated cellulose. Pure, greenish yellow dyeings are obtained with the new dyestufi on cellu- S lose fibers. As compared with the similar known 11.0 dyestuffs described in U. s. Pat. No. 1,159,386

H015 C and the corresponding German Patent No. 293.-

/ 333 which, too, yield greenish yellow dyeings,

N 03H the dyestuffs of the invention, as a rule, are disin which the position of e Sulfonic acid group tinguished by possessing an improved absorptive in the nucleus A has not be accurately detercapacity and fastness to washing and also better mined. dyeing strength. With regard to fastness to light The acetoacetyl-aminobenzenes used as couthey fulfil] the normal requirements p ing com o e y be derived. for example, The following examples illustrate the invenfrom 1-amino-2-a1k0Xy-4- tion, the parts and percentages being by weight zenes. whi contain fluorine bromine, and unless otherwise. states and the relationship of vanta ee y 0111011118, as the halogen- The parts by weight to parts by volume being the koxy group in the Z-POSitiOII advantageously same as that of the kilogram to the liter:

tains only a few, for example, at most 4, carbon Example 1 atoms. The alkoxy group may be a butyloxy or a propyloxy group. However, it is of advantage 25.6 parts of 1-acet0acetylamino-2-methoxy-4- to use the 2-ethoxyor preferably the 2-methoxychloro-5-methy1benzene are dissolved in 250 3 parts of water and 13.5 parts of sodium hydroxide solution of 30 per cent. strength, and 20 parts of crystalline sodium acetate are added. Intothe clear solution is poured in a thin stream while stirring well at room temperature a diazo- 5 solution prepared in known manner from 40 parts of dehydrothio-para-toluidine disulfonic acid (which has been obtained by baking dehydrothio-para-toluidine monosuifonic acid) by means of 25 parts by volume of hydrochloric acid of 30 per cent. strength and the necessary quantity of nitrite. The whole is stirred for 4 hours longer. There is then introduced dropwise an aqueous solution of 10 per cent. strength of an hydrous sodium carbonate until the dyestufi suspension has a reaction alkaline to Brilliant Yellow, and the whole is then heated to 50' C. The dyestuff, which in its free acid state corresponds to the formula is salted out completely by means of a little sodium chloride, separated by iiltration and dried. It is ayellow powder which dissolves in water and in dilute caustic soda solution with a yellow coloration and in concentrated sulfuric acid with an orange coloration. Direct dyeings produced with the dyestuff on cotton or regenerate-d cellulose are greenish yellow.

By using, instead of 1-acetoacetylamino-2- methoxy-4-chloro-5-methylbenzene, 26.95 parts of l-acetoacetylamino 2 ethoxy 4 chloro-5- methylbenzene and otherwise proceeding in the manner described above, there is obtained a dyestufi which in its free acid state corresponds to H3O HO S- the formula which dyes cotton yellow tints of a slightly less greenish shade and possesses an even better absorptive capacity. l acetoacetyzlamino-LZ ethoxy 4 chloro 5 methylbenzene (melting at 133-43? C.) is obtained, for example by con densing ethyl acetoacetate or diketene with 1- amino 2 ethoxy 4 chloro 5 inethyb benzene in ohlorobenzene in the presence of tri-' ethanolamine. l amino 2 ethoxy s 4 chloro- E-methylbenZene may be prepared from 1- formylamino-2-ethoxy-5-methylbenzene by the action of chlorine followed by hydrolysis. It melts at 644-65" C.

By using 30 parts of l-acetoacetylamino-Z- methoxy-4-brorno-5-methylbenzene (obtained by condensing ethyl acetoacetate with 1-'amino=2 methoxy-4=brorno-5=methy1benzene, and melting at 98-99 C.) there is obtained a dyestufi which 2: in its free acid state corresponds to the formula and which dyes fcotton tints of a somewhat less greenish shade than the dyestuii obtainable as described in the first paragraph of this example and has about the same good absorptive capacity.

B'y starting from 31.4 parts or" l-acetoacetylamino-2-ethoxy-4-bromo-5-methylbenzene there is obtained a 'dyestuii which dyes cotton in slightly less greenish yellow tints and. has a somewhat better absorptive capacity than the dyestuff obtainable as described in the first paragraph of this example. l-acetoacetylamino-Z- ethoxyi-bromo-5-methylbenzene melting at 146 C. is obtained, for example, by condensing ethyl acetoacetate or dike'tene with 1-amino-2-ethoxy- 4-bromo-5-methyl benzene. l-amino-2-e'thoxy 4 bromo-5-rnethylbenzene can be obtained from l-formylamino-Z-ethoxy-5-methylbenzene by the action of bromine followed by hydrolysis. It melts at 64.5+65 C.

Example '2 100 parts of cotton are entered into a dyebath at 50 C. containing in 3000 parts of water 0.5 part of the dyestufi obtained as described in the first paragraph of Example 1 and 4 parts of anhydrous sodium carbonate. The temperature is raised to C. in the course or hour and 60 parts of crystalline sodium sulfate are added. Dyeing is carried on for 1 hour at 90- C. and the cotton is dyed a pure greenish yellow tint.

What is claimed is:

1. An azo-dyestufi of the formula wherein the alkyl group contains at most 2 carbon atoms and the halogen is a member selected from the group consisting of chlorine and bromine. v

2. An azo-dyestufi of the formula wherein the alkyl group contains at most 2 carbon atoms.

3. An azo-dyestufi of the formula S CH3 V HO-C H30 OHi HOaS- o N=N-C 1 l (JO-NIPOCI N SOsH I O-alkyl wherein the alkyl group contains at most 2 car-' bon atoms.

2,657,202 5 4. The azo-dystufi of the formula,

CH1 HO-( 5. The azo-dyestufi of the formula s E Number H 0 110-0 1,159,386 HO:S N=Ni 15 2,030,327

O H (BO-NH o1 Number 43111 293,333 6. The azo-dyestuflf of the formula, 883.982

EDUARD MOSER.

19 References Cited in the file of this patent UNITED STATES PATENTS Name Date Huismann Nov. 9, 1915 Schrader et a1. Feb. 11, 1936 FOREIGN PATENTS Country Date Germany Jan. 22, 1914 France Apr. 5, 1943 

1. AN AZO-DYESTUFF OF THE FORMULA 